Composition for dyeing keratinous fibers containing 3 amino pyrazolo- [1,5-a] pyridines, dyeing method, novel 3-amino pyrazolo-[1,5-a] pyridines

ABSTRACT

The invention concerns novel oxidative compositions for dyeing keratinous fibres comprising at least a 3-amino-pyrazolo-[1,5-a]-pyridine of Formula (I), the dyeing method using said composition, novel 3-amino pyrazolo-[1,5-a]-pyridines, and the method for preparing them.

The invention relates to novel compositions for the oxidation dyeing ofkeratinous fibers, comprising at least one3-aminopyrazolo[1,5-a]pyridine as oxidation base, to the dyeing methodemploying this composition, to novel 3-aminopyrazolo[1,5-a]pyridines,and to their use for the oxidation dyeing of keratinous fibers.

It is known to dye keratinous fibers and particularly human hair withdyeing compositions comprising oxidation dye precursors, in particularortho- or para-phenylenediamines, ortho- or para-aminophenols, andheterocyclic compounds such as diaminopyrazole derivatives, which arereferred to generally as oxidation bases. The oxidation dye precursorsor oxidation bases are colorless or virtually colorless compounds which,when combined with oxidizing products, are able to give rise to coloredcompounds and dyes by a process of oxidative condensation. A commonfeature of these compounds is possession of an amino group and ahydroxyl group or of two amino groups, this giving them their characteras oxidation bases.

It is also known that the shades obtained with these oxidation bases canbe varied by combining them with couplers or coloration modifiers, thelatter being selected in particular from aromatic meta-diamines,meta-aminophenols, meta-diphenols, and certain heterocyclic compounds.

The variety of molecules employed as oxidation bases and couplers makesit possible for a rich palette of colors to be obtained.

The “permanent” coloration obtained by means of these oxidation dyes isrequired, moreover, to meet a certain number of requirements. Hence itmust have no toxicological drawbacks, it must allow shades of thedesired intensity to be obtained, and it must exhibit good stability viaa vis external agents (light, inclement weather, washing, perming,perspiration, and friction).

The dyes must also allow white hair to be covered and, finally, theymust be as unselective as possible; in other words, they must allow thesmallest possible differences in coloration to be produced over theentire length of a single keratinous fiber, which may in fact besensitized (i.e., damaged) differently between its tip and its root.

It has already been proposed, particularly in the patents GB 1 026 978and GB 1 153 196, to use pyridines such as 2,5-diaminopyridine,2-(4-methoxyphenyl)amino-3-aminopyridine, 2,3-diamino-6-methoxypyridine,2-(β-methoxyethyl)amino-3-amino-6-methoxypyridine and3,4-diaminopyridine, as oxidation bases for the oxidation dyeing ofkeratinous fibers.

The applicant has now just discovered, completely unexpectedly andsurprisingly, a new class of 3-aminopyrazolo[1,5-a]pyridines, of formula(I) defined hereinbelow, some of which are novel per se, which may besuitable for use as oxidation bases but which, moreover, make itpossible to obtain dyeing compositions which lead to colorations whichare strong even at neutral pH and which exhibit good stability vis a visexternal agents (light, inclement weather, washing, perming,perspiration, and friction).

It is these discoveries which form the basis for the present invention.

Accordingly, the invention first provides a composition for theoxidation dyeing of keratinous fibers, and especially human keratinousfibers such as hair, characterized in that it comprises, in a mediumappropriate for dyeing, at least one 3-aminopyrazolo[1,5-a]pyridine offormula (I) below as oxidation base and/or one of its addition saltswith an acid or with a base:

in which:

R₁, R₂, R₃, R₄ and R₅, which are identical or different, represent ahydrogen or halogen atom; an —NHSO₃H radical; a hydroxyl radical; a(C₁-C₄)alkyl radical; a (C₁-C₄)alkoxy radical; a (C₁-C₄)alkylthioradical; mono(C₁-C₄)alkylamino; a di(C₁-C₄)alkylamino radical in whichthe two alkyl groups, in conjunction with the nitrogen atom to whichthey are bonded, may form a ring which may be interrupted by one or morenitrogen, oxygen or sulfur atoms; a heterocycle; a nitro radical; aphenyl radical; a carbonyl radical; a ((C₁-C₄)alkoxy)carbonyl radical; acarboxamido radical; a cyano radical; an amino radical; a sulfonylradical; a —CO₂H radical, an —SO₃H radical; a —PO₃H2 radical; a —PO₄H₂radical; or a group of formula (II) below:

in which R represents an oxygen or nitrogen atom, X represents an oxygenatom or an NH or NH(C₁-C₄)alkyl group, and Y represents a hydroxyl,amino, C₁-C₄ alkyl, (C₁-C₄)alkoxy, (C₁-C₄)alkylamino ordi(C₁-C₄)alkylamino radical.

In the compounds of formula (I) above, the alkyl term used for the alkylradicals and for the groups containing an alkyl moiety signifies alinear or branched carbon chain containing 1 to 4 carbon atoms which isunsubstituted or substituted by one or more heterocycles or by one ormore phenyl groups or by one or more groups selected from halogen atomssuch as chlorine, bromine, iodine and fluorine; hydroxyl, alkoxy, amino,carbonyl, carboxamido, sulfonyl, —CO₂H, —SO₃H, —PO₃H₂, —PO₄H₂, —NHSO₃H,sulfonamide, monoalkyl (C₁-C₄)amino or trialkyl(C₁-C₄)ammonium radicalsor else by a dialkyl(C₁-C₄)amino radical in which the two alkyl groups,in conjunction with the nitrogen atom of said dialkyl(C₁-C₄)amino groupto which they are bonded, may form a ring which may be interrupted byone or more nitrogen, oxygen or sulfur atoms.

Similarly, as claimed in the invention, the alkoxy term used for thealkoxy radicals and for the groups containing an alkoxy moiety signifiesa linear or branched O-carbon chain containing 1 to 4 of carbon, whichis unsubstituted or substituted by one or more groups selected fromheterocycles; halogen atoms such as chlorine, bromine, iodine andfluorine; hydroxyl, amino, carbonyl, carboxamido, sulfonyl, —CO₂H,—SO₃H, —PO₃H₂, —PO₄H₂, —NHSO₃H, sulfonamide, monoalkyl(C₁-C₄)amino ortrialkyl(C₁-C₄)ammonium radicals or else by a dialkyl(C₁-C₄)aminoradical in which the two alkyl groups, in conjunction with the nitrogenatom of said dialkyl(C₁-C₄)amino group to which they are bonded, mayform a ring which may be interrupted by one or more nitrogen, oxygen orsulfur atoms.

As claimed in the invention, a heterocycle is an aromatic or nonaromaticring containing 5, 6 or 7 members and from 1 to 3 heteroatoms selectedfrom nitrogen, sulfur and oxygen atoms. These heterocycles can becondensed with other heterocycles or with a phenyl group. They can besubstituted by a halogen atom; a (C₁-C₄)alkyl radical; a (C₁-C₄)alkoxyradical; a hydroxyl radical; an amino radical; a (C₁-C₄)alkylaminoradical; di(C₁-C₄)alkylamino in which the two alkyl groups, inconjunction with the nitrogen atom to which they are bonded, may form aring which may be interrupted by one or more nitrogen, oxygen or sulfuratoms. These heterocycles may additionally be quaternized by a(C₁-C₄)alkyl radical.

Among these heterocycles, mention may be made in particular, by way ofexample, of the following rings: thiadiazole, triazole, isoxazole,oxazole, azaphosphole, thiazole, isothiazole, imidazole, pyrazole,triazine, thiazine, pyrazine, pyridazine, pyrimidine, pyridine,diazepin, oxazepin, benzotriazole, benzoxazole, benzimidazole,benzothiazole, morpholine, piperidine, piperazine, azetidine,pyrrolidine, aziridine, 3-(2-hydroxyethyl)benzothiazol-3-ium and1-(2-hydroxyethyl)pyridinium.

As claimed in the invention, phenyl means a phenyl radical which isunsubstituted or substituted by one or more cyano, carbonyl,carboxamido, sulfonyl, —CO₂H, —SO₃H, —PO₃H₂, —PO₄H₂, hydroxyl, amino,monoalkyl(C₁-C₄)amino or dialkyl(C₁-C₄)amino radicals in which the twoalkyl groups, in conjunction with the nitrogen atom of saiddialkyl(C₁-C₄)amino group to which they are bonded, may form a ringwhich may be interrupted by one or more nitrogen, oxygen or sulfuratoms.

Among the groups of formula (II) above, mention may be made inparticular of the groups acetamide, dimethylurea, O-methylcarbamate,methylcarbonate, N-dimethylcarbamate and the esters.

Among the compounds of formula (I) above, preference is given to3-aminopyrazolo[1,5-a]pyridines of subformula (Ia) below and theiraddition salts with an acid or with a base:

in which:

R₁, R₂ and R₃, which are identical or different, represent a hydrogen orhalogen atom; a hydroxyl radical; a (C₁-C₄)alkyl radical; a(C₁-C₄)alkylthio radical; a (C₁-C₄)alkoxy radical; an —NHSO₃H radical;an amino radical; a (C₁-C₄)alkylamino radical; a di(C₁-C₄)alkylaminoradical in which the two alkyl groups, in conjunction with the nitrogenatom to which they are bonded, may form a ring which may be interruptedby one or more nitrogen, oxygen or sulfur atoms; a heterocycle asdefined above; a sulfonamide radical; a carbonyl radical; a((C₁-C₄)alkoxy)carbonyl radical; a carboxamido radical; or a group offormula (II) below:

in which R represents an oxygen or nitrogen atom, X represents an oxygenatom or an NH or NH(C₁-C₄)alkyl group, and Y represents a hydroxyl,amino, C₁-C₄ alkyl, (C₁-C₄)alkoxy, (C₁-C₄)alkylamino ordi(C₁-C₄)alkylamino radical.

Among the 3-aminopyrazolo[1,5-a]pyridines of formula (I) which can beused as oxidation bases in the dyeing compositions of the invention,mention may be made in particular of:

pyrazolo[1,5-a]pyridin-3-ylamine;

2-acetylaminopyrazolo[1,5-a]pyridin-3-ylamine;

2-morpholin-4-ylpyrazolo[1,5-a]pyridin-3-ylamine;

3-aminopyrazolo[1,5-a]pyridine-2-carboxylic acid;

2-methoxypyrazolo[1,5-a]pyridin-3-ylamin;

(3-aminopyrazolo[1,5-a]pyridin-7-yl)methanol;

2-(3-aminopyrazolo[1,5-a]pyridin-5-yl)ethanol;

2-(3-aminopyrazolo[1,5-a]pyridin-7-yl)ethanol;

(3-aminopyrazolo[1,5-a]pyridin-2-yl)methanol;

3,6-diaminopyrazolo[1,5-a]pyridine;

3,4-diaminopyrazolo[1,5-a]pyridine;

pyrazolo[1,5-a]pyridine-3,7-diamine;

7-morpholin-4-ylpyrazolo[1,5-a]pyridin-3-ylamine;

pyrazolo[1,5-a]pyridine-3,5-diamine;

5-morpholin-4-ylpyrazolo[1,5-a]pyridin-3-ylamine;

2-[(3-aminopyrazolo[1,5-a]pyridin-5-yl)-(2-hydroxyethyl)amino]ethanol;

2-[(3-aminopyrazolo[1,5-a]pyridin-7-yl)-(2-hydroxyethyl)amino]ethanol;

3-aminopyrazolo[1,5-a]pyridin-5-ol;

3-aminopyrazolo[1,5-a]pyridin-4-ol;

3-aminopyrazolo[1,5-a]pyridin-6-ol;

3-aminopyrazolo[1,5-a]pyridin-7-ol;

and their addition [lacuna] with an acid or with a base.

The great majority of the 3-aminopyrazolo[1,5-a]pyridines of formula (I)are compounds which are known in the pharmaceutical field and aredescribed in particular in the patent U.S. Pat. No. 5,457,200. Thesecompounds can be prepared by synthesis methods which are well known inthe literature, such as are described, for example, in the patent U.S.Pat. No. 5,457,200.

The 3-aminopyrazolo[1,5-a]pyridine(s) of formula (I) above and/or the ortheir addition salts with an acid or a base make(s) up preferably from0.0005 to 12% by weight approximately of the total weight of the dyeingcomposition and more preferably still from 0.005 to 6% by weightapproximately of this weight.

The medium appropriate for dyeing (or vehicle) generally consists ofwater or of a mixture of water and at least one organic solvent forsolubilizing the compounds which would not be sufficiently soluble inwater. As organic solvent mention may be made, for example, of C₁-C₄lower alkanols, such as ethanol and isopropanol; glycerol; glycols andglycol ethers such as 2-butoxyethanol, propylene glycol, propyleneglycol monomethyl ether, and diethylene glycol monoethyl ether andmonomethyl ether, and aromatic alcohols such as benzyl alcohol orphenoxyethanol, similar products and mixtures thereof.

The solvents may be present in proportions of preferably between 1 and40% by weight approximately relative to the total weight of the dyeingcomposition and more preferably still between 5 and 30% by weightapproximately.

The pH of the dyeing composition of the invention is generally betweenapproximately 3 and 12 and preferably between approximately 5 and 11. Itcan be adjusted to the desired value using acidifying or basifyingagents which are commonly used in dyeing keratinous fibers or else bymeans of conventional buffer systems.

Among the acidifying agents mention may be made, by way of example, ofmineral or organic acids such as hydrochloric acid, ortho-phosphoricacid, sulfuric acid, carboxylic acids such as acetic acid, tartaricacid, citric acid and lactic acid, and sulfonic acids.

Among the basifying agents mention may be made, by way of example, ofaqueous ammonia, alkali metal carbonates, alkanolamines such as mono-,di- and triethanolamines and their derivatives, sodium hydroxide orpotassium hydroxide, and the compounds of formula (III) below:

in which W is a propylene residue optionally substituted by a hydroxylgroup or a C₁-C₄ alkyl radical; and R₆, R₇, R₈ and R₉, which areidentical or different, represent a hydrogen atom or a C₁-C₄ alkyl orhydroxyalkyl radical.

In accordance with one preferred embodiment, the oxidation dyeingcomposition of the invention further comprises one or more couplers inorder to modify or enrich with glints the shades obtained employing thecompounds of formula (I).

The couplers which can be used in the oxidation dyeing compositions ofthe invention may be selected from the couplers employed conventionallyin oxidation dyeing, among which particular mention maybe made ofmeta-phenylenediamines, meta-aminophenols, meta-diphenols andheterocyclic couplers.

These couplers are selected more particularly from2-methyl-5-aminophenol, 5-N-(O-hydroxyethyl)amino-2-methylphenol,3-aminophenol, 1,3-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene,4-chloro-1,3-dihydroxybenzene, 2,4-diamino-1-(β-hydroxyethyloxy)benzene,2-amino-4-(β-hydroxyethylamino)-1-methoxybenzene, 1,3-diaminobenzene,1,3-bis(2,4-diaminophenoxy)propane, sesamol, α-naphthol,2-methyl-1-naphthol, 6-hydroxyindole, 4-hydroxyindole,4-hydroxy-N-methylindole, 6-hydroxyindoline,2,6-dihydroxy-4-methylpyridine, 1H-3-methylpyrazol-5-one,1-phenyl-3-methylpyrazol-5-one, and their addition salts.

When present, the coupler(s) make(s) up preferably from 0.0001 to 10% byweight approximately of the total weight of the dyeing composition andmore preferably still from 0.005 to 5% by weight approximately of thisweight.

The dyeing composition of the invention may further comprise, inaddition to the dyes defined above, at least one additional oxidationbase which may be selected from the oxidation bases used conventionallyin oxidation dyeing and among which mention may be made in particular ofpara-phenylenediamines, bisphenylalkylenediamines, para-aminophenols,ortho-aminophenols and heterocyclic bases other than the3-aminopyrazolo[1,5-a]pyridines of formula (I) used in accordance withthe invention.

Among the para-phenylenediamines, mention may be made more particularly,by way of example, of para-phenylenediamine, para-tolylenediamine,2-chloro-para-phenylenediamine, 2,3-dimethyl-para-phenylenediamine,2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine,2,5-dimethyl-para-phenylenediamine, N,N-dimethyl-para-phenylenediamine,N,N-diethyl-para-phenylenediamine, N,N-dipropyl-para-phenylenediamine,4-amino-N,N-diethyl-3-methylaniline,N,N-bis(β-hydroxyethyl)-para-phenylenediamine,4-N,N-bis(β-hydroxyethyl)amino-2-methylaniline,4-N,N-bis(β-hydroxyethyl)amino-2-chloroaniline,2-β-hydroxyethyl-para-phenylenediamine, 2-fluoro-para-phenylenediamine,2-isopropyl-para-phenylenediamine,N-(β-hydroxypropyl)-para-phenylenediamine,2-hydroxymethyl-para-phenylenediamine,N,N-dimethyl-3-methyl-para-phenylenediamine, N,N-(ethyl,β-hydroxyethyl)-para-phenylenediamine,N-(β,γ-dihydroxypropyl)-para-phenylenediamine,N-(4′-aminophenyl)-para-phenylenediamine,N-phenyl-para-phenylenediamine,2-β-hydroxyethyloxy-para-phenylenediamine,2-β-acetylaminoethyloxy-para-phenylenediamine,N-(β-methoxyethyl)-para-phenylenediamine, and their addition salts withan acid.

Among the abovementioned para-phenylenediamines, very particularpreference is given to para-phenylenediamine, para-tolylenediamine,2-isopropyl-para-phenylenediamine,2-β-hydroxyethyl-para-phenylenediamine,2-β-hydroxyethyloxy-para-phenylenediamine,2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine,2,3-dimethyl-para-phenylenediamine,N,N-bis(p-hydroxyethyl)-para-phenylenediamine,2-chloro-para-phenylenediamine,2-β-acetylaminoethyloxy-para-phenylenediamine, and their addition saltswith an acid.

Among the bisphenylalkylenediamines mention may be made moreparticularly, by way of example, ofN,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)-1,3-diaminopropanol,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)ethylenediamine,N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(4-methylaminophenyl)tetramethylenediamine,N,N′-bis(ethyl)-N,N′-bis(4′-amino-3′-methylphenyl)ethylenediamine,1,8-bis(2,5-diaminophenoxy)-3,5-dioxaoctane, and their addition saltswith an acid.

Among the para-aminophenols, mention may be made more particularly, byway of example, of para-aminophenol, 4-amino-3-methylphenol,4-amino-3-fluorophenol, 4-amino-3-hydroxymethylphenol,4-amino-2-methylphenol, 4-amino-2-hydroxymethylphenol,4-amino-2-methoxymethylphenol, 4-amino-2-aminomethylphenol,4-amino-2-(β-hydroxyethylaminomethyl)phenol, 4-amino-2-fluorophenol, andtheir addition salts with an acid.

Among the ortho-aminophenols, mention may be made more particularly, byway of example, of 2-aminophenol, 2-amino-5-methylphenol,2-amino-6-methylphenol, 5-acetamido-2-aminophenol, and their additionsalts with an acid.

Among the heterocyclic bases, mention may be made more particularly, byway of example, of pyridine derivatives other than the compounds offormula (I) of the invention, pyrimidine derivatives and pyrazolederivatives.

Among the pyridine derivatives other than the compounds of formula (I)of the invention, mention may be made more particularly of the compoundsdescribed for example in the patents GB 1 026 978 and GB 1 153 196, suchas 2,5-diaminopyridine, 2-(4-methoxyphenyl)amino-3-aminopyridine,2,3-diamino-6-methoxypyridine,2-(-methoxyethyl)amino-3-amino-6-methoxypyridine, 3,4-diaminopyridine,and their addition salts with an acid.

Among the pyrimidine derivatives mention may be made more particularlyof the compounds described for example in the patents DE 2 359 399; JP88-169 571; JP 05 163 124; EP 0 770 375, or patent application WO96/15765, such as 2,4,5,6-tetraaminopyrimidine,4-hydroxy-2,5,6-triaminopyrimidine, 2-hydroxy-4,5,6-triaminopyrimidine,2,4-dihydroxy-5,6-diaminopyrimidine, 2,5,6-triaminopyrimidine, and thepyrazolopyrimidine derivatives such as those mentioned in the patentapplication FR-A-2 750 048, among which mention may be made ofpyrazolo[1,5-a]pyrimidine-3,7-diamine;2,5-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine;pyrazolo[1,5-a]pyrimidine-3,5-diamine;2,7-dimethylpyrazolo[1,5-a]pyrimidine-3,5-diamine;3-aminopyrazolo[1,5-a]pyrimidin-7-ol;3-aminopyrazolo[1,5-a]pyrimidin-5-ol;2-(3-aminopyrazolo[1,5-a]pyrimidin-7-ylamino)ethanol,2-(7-aminopyrazolo[1,5-a]pyrimidin-3-ylamino)ethanol,2-[(3-aminopyrazolo[1,5-a]pyrimidin-7-yl)-(2-hydroxyethyl)amino]ethanol,2-[(7-aminopyrazolo[1,5-a]pyrimidin-3-yl)-(2-hydroxyethyl)amino]ethanol,5,6-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine,2,6-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine,2,5,N7,N7-tetramethylpyrazolo[1,5-a]pyrimidine-3,7-diamine,3-amino-5-methyl-7-imidazolylpropylaminopyrazolo[1,5-a]pyrimidine andtheir addition salts with an acid and, where a tautomeric equilibriumexists, their tautomeric forms.

Among the pyrazole derivatives mention may be made more particularly ofthe compounds described in the patents DE 3 843 892, DE 4 133 957 andpatent applications WO 94/08969, WO 94/08970, FR-A-2 733 749 and DE 19543 988 such as 4,5-diamino-1-methylpyrazole,4,5-diamino-1-(β-hydroxyethyl)pyrazole, 3,4-diaminopyrazole,4,5-diamino-1-(4′-chlorobenzyl)pyrazole,4,5-diamino-1,3-dimethylpyrazole, 4,5-diamino-3-methyl-1-phenylpyrazole,4,5-diamino-1-methyl-3-phenylpyrazole,4-amino-1,3-dimethyl-5-hydrazinopyrazole,1-benzyl-4,5-diamino-3-methylpyrazole,4,5-diamino-3-tert-butyl-1-methylpyrazole,4,5-diamino-1-tert-butyl-3-methylpyrazole,4,5-diamino-1-(β-hydroxyethyl)-3-methylpyrazole,4,5-diamino-1-ethyl-3-methylpyrazole,4,5-diamino-1-ethyl-3-(4′-methoxyphenyl)pyrazole,4,5-diamino-1-ethyl-3-hydroxymethylpyrazole,4,5-diamino-3-hydroxymethyl-1-methylpyrazole,4,5-diamino-3-hydroxymethyl-1-isopropylpyrazole,4,5-diamino-3-methyl-1-isopropylpyrazole,4-amino-5-(2′-aminoethyl)amino-1,3-dimethylpyrazole,3,4,5-triaminopyrazole, 1-methyl-3,4,5-triaminopyrazole,3,5-diamino-1-methyl-4-methylaminopyrazole,3,5-diamino-4-(β-hydroxyethyl)amino-1-methylpyrazole, and their additionsalts with an acid.

Where used, the additional oxidation base(s) make(s) up preferably from0.0005 to 12% by weight approximately of the total weight of the dyeingcomposition and more preferably still from 0.005 to 6% by weightapproximately of this weight.

Generally speaking, the addition salts with an acid that can be used inthe context of the dyeing compositions of the invention (compounds offormula (I), (Ia), additional oxidation bases, and couplers) areselected in particular from hydrochlorides, hydrobromides, sulfates,citrates, succinates, tartrates, lactates, phosphates and acetates. Theaddition salts with a base that can be used in the context of the dyeingcompositions of the invention are in particular those obtained withsodium hydroxide, potassium hydroxide, aqueous ammonia or amines.

The dyeing composition of the invention may further comprise one or moredirect dyes which can be selected in particular from the nitro dyes ofthe benzene series.

The dyeing composition of the invention may further comprise variousadjuvants conventionally used in compositions for dyeing hair, such asanionic, cationic, nonionic, amphoteric or zwitterionic surfactants ormixtures thereof, anionic, cationic, nonionic, amphoteric orzwitterionic polymers or mixtures thereof, mineral or organicthickeners, antioxidants, penetrants, sequestrants, perfumes, buffers,dispersants, conditioners such as, for example, volatile or nonvolatile,modified or unmodified silicones, film formers, ceramides, preservativesand opacifiers.

The person skilled in the art will of course take care to select theabovementioned optional complementary compound(s) in such a way that theadvantageous properties intrinsic to the oxidation dyeing composition ofthe invention are not, or not substantially, impaired by the intendedaddition or additions.

The dyeing composition of the invention may be in any of a variety offorms, such as in liquid, cream, gel or any other form appropriate fordyeing keratinous fibers and especially human hair.

The invention likewise provides a method of dyeing keratinous fibers andespecially human keratinous fibers such as hair, employing the dyeingcomposition as defined above.

As claimed in this method, at least one dyeing composition as definedabove is applied to the fibers, the color being developed at acid,neutral or alkaline pH by means of an oxidizing agent which is added tothe dyeing composition at the time of use or which is present in anoxidizing composition applied simultaneously or sequentially.

As claimed in one preferred embodiment of the dyeing method of theinvention, the dyeing composition described above is mixed preferably atthe time of use with an oxidizing composition comprising, in a mediumappropriate for dyeing, at least one oxidizing agent in an amountsufficient to develop a coloration. The mixture obtained is then appliedto the keratinous fibers and left to act for approximately 3 to 50minutes, preferably approximately 5 to 30 minutes, after which saidfibers are rinsed, washed with shampoo, rinsed again and dried.

The oxidizing agent may be selected from oxidizing agents conventionallyused for the oxidation dyeing of keratinous fibers, among which mentionmay be made of hydrogen peroxide, urea peroxide, alkali metal bromates,persalts such as perborates and persulfates, and enzymes, among whichmention may be made of peroxidases, 2-electron oxidoreductases such asuricases, and 4-electron oxygenases such as laccases. Hydrogen peroxideis particularly preferred.

The pH of the oxidizing composition comprising the oxidizing agent asdefined above is such that, following its mixture with the dyeingcomposition, the pH of the resulting composition applied to thekeratinous fibers varies preferably between approximately 3 and 12 andmore preferably still between 5 and 11. It is adjusted to the desiredvalue by means of acidifying or basifying agents which are commonly usedin dyeing keratinous fibers and which are such as defined above.

The oxidizing composition as defined above may further comprise variousadjuvants which are conventionally used in compositions for dyeing hairand which are such as defined above.

The composition which is finally applied to the keratinous fibers may bepresent in various forms, such as in liquid, cream, gel or any otherform appropriate for dyeing keratinous fibers and especially human hair.

The invention further provides a multicompartment dyeing device or kitor any other multicompartment packaging system of which a firstcompartment contains the dyeing composition as defined above and asecond compartment contains the oxidizing composition as defined above.These devices may be equipped with a means enabling the desired mixtureto be delivered onto the hair, such as the devices described in theapplicant's patent FR-2 586 913.

Certain compounds of formula (I) used as oxidation bases in the contextof the present invention are novel and are therefore also provided bythe invention.

These novel 3-aminopyrazolo[1,5-a]pyridines and their addition saltswith an acid or with a base are of the following formula (I′):

in which:

R′₁ represents a hydrogen or halogen atom; a hydroxyl radical;(C₁-C₄)alkyl; a (C₁-C₄)alkylthio radical; a (C₁-C₄)alkoxy radical; anamino radical; a (C₁-C₄)alkylamino radical; a di(C₁-C₄)alkylaminoradical in which the two alkyl groups, in conjunction with the nitrogenatom to which they are bonded, may form a ring which may be interruptedby one or more nitrogen, oxygen or sulfur atoms; a heterocycle; or agroup of formula (II′) below:

in which R′ represents an oxygen or nitrogen atom, X′ represents anoxygen atom or an NH or NH(C₁-C₄)alkyl group, and Y′ represents ahydroxyl, amino, C₁-C₄ alkyl, (C₁-C₄)alkoxy, (C₁-C₄)alkylamino ordi(C₂-C₄)alkylamino radical;

R′₂ and R′₃, which are identical or different, represent a hydrogenatom; a halogen atom; a nitro radical; a heterocycle; an NHSO₃H radical;a sulfonamide radical; a (C₁-C₄)alkyl radical substituted by one or moreidentical or different radicals selected from heterocycles, —CO₂H,—SO₃H, —PO₃H₂, —PO₄H₂, hydroxyl, tri(C₁-C₄)alkylammonium, —NHSO₃H,sulfonamide, amino, (C₁-C₄)alkylamino and di(C₁-C₄)alkylamino radicalsin which the two alkyl radicals, in conjunction with the nitrogen atomto which they are bonded, may form a ring which may be interrupted byone or more nitrogen, sulfur or oxygen atoms; a (C₁-C₄)alkylthio radicalsubstituted by one or more hydroxyl or substituted or unsubstitutedamino radicals or by one or more —CO₂H, —SO₃H, —PO₃H₂ or —PO₄H₂ groupsor by one or more heterocycles; a (C₁-C₄)alkoxy radical substituted byone or more hydroxyl or substituted or unsubstituted amino radicals orby one or more —CO₂H, —SO₃H, —PO₃H₂ or —PO₄H₂ groups or by one or moreheterocycles; an amino radical substituted by one or two (C₁-C₄)alkylradicals, said alkyl radical or radicals being itself or themselvessubstituted by a substituted or unsubstituted amino,tri(C₁-C₄)alkylammonium, —CO₂H, —SO₃H, —PO₃H₂, —PO₄H₂ or —NHSO₃H radicalor by a heterocycle; with the proviso that:

at least one of the radicals R′₁ to R′₃ is other than a hydrogen atom;

the radicals R′₂ and R′₃ cannot simultaneously represent a hydrogenatom;

when R′₁ represents a heterocycle, R′₂ and R′₃ are other than a halogenatom and a hydrogen atom;

when R′₁ represents a hydrogen atom and when one of the radicals R′₂ orR′₃ also represents a hydrogen atom, the other radical R′₂ or R′₃ isother than a hydroxymethyl radical in position 7 or than aβ-hydroxyethyl radical in position 7 or 5;

when R′₁ represents a methoxy radical and when one of the radicals R′₂or R′₃ represents a hydrogen atom, the other radical R′₂ or R′₃ is otherthan a chlorine atom.

In the compounds of formula (I′) above, the heterocycle term signifiesan aromatic or nonaromatic ring containing 5, 6 or 7 members and from 1to 3 heteroatoms selected from nitrogen, sulfur and oxygen atoms. Theseheterocycles can be condensed with other heterocycles or with a phenylgroup. They can be substituted by a halogen atom; a (C₁-C₄)alkylradical; a (C₁-C₄)alkoxy radical; a hydroxyl radical; an amino radical;a (C₁-C₄)alkylamino radical; di(C₁-C₄)alkylamino in which the two alkylgroups, in conjunction with the nitrogen atom to which they are bonded,may form a ring which may be interrupted by one or more nitrogen, oxygenor sulfur atoms. These heterocycles may additionally be quaternized by a(C₁-C₄)alkyl radical.

Among these heterocycles, mention may be made in particular, by way ofexample, of the following rings: thiadiazole, triazole, isoxazole,oxazole, azaphosphole, thiazole, isothiazole, imidazole, pyrazole,triazine, thiazine, pyrazine, pyridazine, pyrimidine, pyridine,diazepin, oxazepin, benzotriazole, benzoxazole, benzimidazole,benzothiazole, morpholine, piperidine, piperazine, azetidine,pyrrolidine, aziridine, 3-(2-hydroxyethyl)benzothiazol-3-ium and1-(2-hydroxyethyl)pyridinium.

Among the groups of formula (II′) above, mention may be made inparticular of the groups acetamide, dimethylurea, O-methylcarbamate,methylcarbonate, N-dimethylcarbamate and the esters.

Among the 3-aminopyrazolo[1,5-a]pyridines of formula (I′) above, mentionmay be made in particular of:

5-pyridin-4-ylpyrazolo[1,5-a]pyridin-3-ylamine;

4-(3-aminopyrazolo[1,5-a]pyridin-5-yl)-1-methylpyridinium;

4-(3-aminopyrazolo[1,5-a]pyridin-5-yl)-1-(2-hydroxyethyl)pyridinium;

(3-aminopyrazolo[1,5-a]pyridin-2-yl)pyridin-2-ylmethanol;

2-[(3-aminopyrazolo[1,5-a]pyridin-2-yl)hydroxymethyl]-1-methylpyridinium;

2-[(3-aminopyrazolo[1,5-a]pyridin-2-yl)hydroxymethyl]-1-(2-hydroxyethyl)pyridinium;

N-7-(2-imidazo-1-ylpropyl)pyrazolo[1,5-a]pyridine-3,7-diamine;

3-[2-(3-aminopyrazolo[1,5-a]pyridin-7-ylamino)propyl]-1-methyl-3H-imidazol-1-ium;

3-[2-(3-aminopyrazolo[1,5-a]pyridin-7-ylamino)propyl]-1-(2-hydroxyethyl)-3H-imidazol-1-ium;

N-5-(3-imidazo-1-ylpropyl)pyrazolo[1,5-a]pyridine-3,5-diamine;

3-[3-(3-aminopyrazolo[1,5-a]pyridin-5-ylamino)propyl]-1-methyl-3H-imidazol-1-ium;

3-[3-(3-aminopyrazolo[1,5-a]pyridin-5-ylamino)propyl]-1-(2-hydroxyethyl)-3H-imidazol-1-ium;

and their addition salts with an acid or with a base.

The addition salts with an acid of the compounds of formula (I′) aboveare selected preferably from hydrochlorides, hydrobromides, sulfates,citrates, succinates, tartrates, lactates, phosphates and acetates. Theaddition salts with a base of the compounds of formula (II) above areselected preferably from those obtained with sodium hydroxide, potassiumhydroxide, aqueous ammonia or amines.

These novel 3-aminopyrazolo[1,5-a]pyrimidines of formula (I′) above,and, more generally, the 3-aminopyrazolo[1,5-a]pyridines of formula (I)described above, may be prepared by methods which are known and aredescribed in the literature, and, for example, in accordance with thefollowing synthesis scheme:

in accordance with which a compound A is aminated for example with—NH₂SO₃H or NH₂SO₃MS (o-mesitylcnesulfonylhydroxylamine) to give acompound B, with conversion of the sulfate salt to the iodide salt.These amination reactions are described in particular in J. Org. Chem.33 (1968) 3766; Chem. Pharm. Bull. 22 (1974) 482; Tet. Lett. (1972)4133; Synthesis (1977) 1; or else in Bull. Chem. Soc. Jpn. 49 (1976)1980.

The compound C can then be obtained by 1,3-dipolar cyclization of thecompound B with methyl or ethyl propiolate. This cyclization reaction isdescribed in Liebigs Ann. Chem. (1977) 498; Tet. Lett. (1962) 387; Arch.Pharm. 321 (1988) 505; J. Het. Chem. 18 (1981) 1149; Het. 24 (1986)3411; Biorg. Med. Chem. Lett. 3 (1993) 1477.

The compound C is converted into compound D following hydrolysis of theester to give the corresponding acid, followed by a decarboxylation; seeLiebigs Ann. Chem. (1977) 498; J. Het. Chem. 18 (1981) 1149.

The introduction of a radical R denoting a nitro, nitroso or arylazogroup starting from the compound D to give the compound E is carried outin accordance with methods described in the literature. The nitrationcan, for example, be carried out with nitric acid, nitric acid mixedwith sulfuric acid, or nitric acid mixed with acetic acid. Thenitrosation can, for example, be carried out with nitrous acid. Anarylazo radical can be introduced by reacting the aryldiazonium saltwith the compound D.

These methods are described in “Nitration Method and Mechanism”, G.Olah, R. Malhotra, S. Narang, VCH Publishers; Houben-Weyl, Methoden derOrganischen Chemie, Vol. 10/1 and 10/3; U.S. Pat. No. 5,457,200; J.Heterocycl. Chem. 11 (1974) 223-225.

The nitro, nitroso and arylazo groups are subsequently reduced to give acompound F in accordance with methods described in the literature. Thereduction can be carried out, for example, with zinc in acetic acid,glacial acetic acid and sodium dithionite, tin chloride in an acid, orelse by catalytic hydrogenation. See in particular Houben-Weyl, Methodender Organischen Chemie, Vol. 10/1 and 10/3; U.S. Pat. No. 5,457,200.

The starting pyridines (compounds A) have been described or can beprepared by analogy with known compounds. Regarding the preparation ofpyridines, see Comprehensive Heterocyclic Chemistry II Vol. 5, A.Katritzky, C. Rees, E. Scriven.

The compounds of general formula (I) or (I′) substituted in position 2can be prepared by analogy with J. Het. Chem. (1975) 481; Chem. Pharm.Bull. 21 (1973) 2146.

The invention lastly provides for the use of3-aminopyrazolo[1,5]pyridines of formulae (I), (Ia) or (I′) and theiraddition salts with an acid or with a base as oxidation bases for theoxidation dyeing of keratinous fibers and especially human keratinousfibers such as hair.

The examples which follow are intended to illustrate the invention.

SYNTHESIS EXAMPLES Example 1 Synthesis of3,4-Diaminopyrazolo[1,5-a]pyridine Dihydrochloride

0.7 g of 3,4-dinitropyrazolo[1,5-a]pyridine was added to a suspension of11.1 g of tin chloride in 80 ml of concentrated hydrochloric acid. Thereaction was monitored by thin layer chromatography (TLC). The pH of thereaction mixture was adjusted to 12 using sodium hydroxide. The aqueousphase was extracted with ethyl acetate and the organic phase was driedover sodium sulfate. The organic phase was acidified with 3 ml ofhydrochloric ethanol (2.5 N HCl). The precipitate was filtered off. Thisgave 0.55 g of pyrazolo[1,5-a]pyridine-3,4-diamine hydrochloride, whose¹H NMR analysis (DMSO-d₆, 400 MHz) (δ ppm) was as follows:

1H NMR (DMSO d₆): 6.82 (d, 1H); 6.97 (d, 1H); 8.18 (s, 1H); 8.36 (d,1H).

Example 2 Synthesis of 3,6-Diaminopyrazolo[1,5-a]pyridine

a) First Step: Preparation of 3,6-Dinitropyrazolo[1,5-a]pyridine byNitration of Pyrazolo[1,5-a]pyridine in Accordance With J. Heterocycl.Chem. 11 (1974) 223-225

3.75 ml of concentrated nitric acid were added to a solution of 4.5 g ofpyrazolo[1,5-a]pyridine in 20 ml of concentrated sulfuric acid. Thereaction was monitored by gas chromatography. After 4 hours of reaction,1 ml of nitric acid was added. The reaction mixture was poured onto 200ml of ice and the precipitate was filtered off.

The product was obtained as a mixture with3,4-dinitropyrazolo[1,5-a]pyridine and isolated by flash chromatographyon silica. ¹H NMR analysis (DMSO d₆, 400 MHz) (δ ppm) was as follows:

1H NMR (DMSO d6): 10.15 (d, 1H); 9.16 (s, 1H); 8.50 (dd, 1H); 8.36 (d,1H).

b) Second Step: Preparation of Pyrazolo[1,5-a]pyridine-3,6-diamine

The reduction of 3,6-dinitropyrazolo[1,5-a]pyridine was carried outusing zinc in an ethanol/water mixture.

MS (chemical ionization at atmospheric pressure): MH⁺ 149.1.

DYEING EXAMPLES Examples 1 to 5 Dyeing in an Alkaline Medium

The following dyeing compositions of the invention were prepared:

COMPOSITION 1 2 3 4 5 3,4-Diaminopyrazolo[1,5-a] 3 × 10⁻³ — — — —pyridine dihydrochloride mol (oxidation base of formula (I))Pyrazolo[1,5-a]pyridin-3-ylamine — 3 × 10⁻³ 3 × 10⁻³ 3 × 10⁻³ —hydrochloride (oxidation base of mol mol mol formula (I))2-Acetylaminopyrazolo [1,5- — — — — 3 × 10⁻³ a] pyridin-3-ylamine molhydrochloride (oxidation base of formula (I)) 2,4-Diamino-1-(β-hydroxy-3 × 10⁻³ — 3 × 10⁻³ — 3 × 10⁻³ ethyloxy)benzene (coupler) mol mol mol3-Aminophenol (coupler) — 3 × 10⁻³ — — — mol 6-Hydroxyindole (coupler) —— — 3 × 10⁻³ — mol Common dyeing vehicle 1 (*) (*) (*) (*) (*)Demineralized water q.s. 100 g 100 g 100 g 100 g 100 g (*) Common dyeingvehicle 1:

96° ethyl alcohol 18 g

35% aqueous sodium metabisulfite solution 0.68 g

Pentasodium salt of diethylenetriamine-pentaacetic acid 1.1 g

20% aqueous ammonia 10.0 g

Demineralized water q.s. 100 g

Each of the above dyeing compositions was mixed weight for weight at thetime of use with a 20 volume hydrogen peroxide solution (6% by weight)with a pH of 3.

Each of the mixtures obtained was applied to locks of natural gray haircontaining 90% white hairs for 30 minutes. The locks were subsequentlyrinsed, washed with a standard shampoo, rinsed again and then dried.

The shades obtained are given in the table below:

EXAMPLE Dyeing pH Shade obtained 1 10 ± 0.2 Ash blond 2 10 ± 0.2Iridescent mahogany 3 10 ± 0.2 Dark purple 4 10 ± 0.2 Coppery gold 5 10± 0.2 Slightly mauvish ashen

Examples 6 to 10 Dyeing in a Neutral Medium

The following dyeing compositions of the invention were prepared:

COMPOSITION 6 7 8 9 10 3,4-Diaminopyrazolo[1,5-a] 3 × 10⁻³ — — — —pyridine dihydrochloride mol (oxidation base of formula (I))Pyrazolo[1,5-a]pyridin-3-ylamine — 3 × 10⁻³ 3 × 10⁻³ 3 × 10⁻³ —hydrochloride (oxidation base of mol mol mol formula (I))2-Acetylaminopyrazolo [1,5- — — — — 3 × 10⁻³ a] pyridin-3-ylamine molhydrochloride (oxidation base of formula (I)) 2,4-Diamino-1-(β-hydroxy-3 × 10⁻³ — 3 × 10⁻³ — 3 × 10⁻³ ethyloxy)benzene (coupler) mol mol mol5-N-(β-Hydroxyethyl)amino-2- — 3 × 10⁻³ — — — methylphenol (coupler) mol6-Hydroxyindole (coupler) — — — 3 × 10⁻³ — mol Common dyeing vehicle 2(**) (**) (**) (**) (**) Demineralized water q.s. 100 g 100 g 100 g 100g 100 g (**) Common dyeing vehicle 2:

96° ethanol 18 g

K₂HPO₄/KH₂PO₄ buffer (1.5M/1M) 10 g

Sodium metabisulfite 0.68 g

Pentasodium salt of diethylenetriamine-pentaacetic acid 1.1 g

Each of the above dyeing compositions was mixed weight for weight at thetime of use with a 20 volume hydrogen peroxide solution (6% by weight)with a pH of 3.

The mixture obtained was applied to locks of natural gray haircontaining 90% white hairs for 30 minutes. The locks were subsequentlyrinsed, washed with a standard shampoo, rinsed again and then dried.

The shades obtained are given in the table below:

EXAMPLE Dyeing pH Shade obtained 6 5.7 ± 0.2 Slightly matte ashen 7 5.7± 0.2 Coppery gold 8 5.7 ± 0.2 Iridescent dark purple 9 5.7 ± 0.2Mahogany gold 10  5.7 ± 0.2 Very slightly iridescent ashen

What is claimed is:
 1. A composition for oxidation dyeing of keratinousfibers, comprising, in a medium appropriate for dyeing, at least oneoxidation base chosen from 3-aminopyrazolo[1,5-a]pyridines of formula(I), acid addition salts thereof, and base addition salts thereof:

in which: R₁, R₂, R₃, R₄ and R₅ are each independently chosen from:hydrogen; a halogen; an —NHSO₃H radical; a hydroxyl radical; a(C₁-C₄)alkyl radical; a (C₁-C₄)alkoxy radical; a (C₁-C₄)alkylthioradical; a (C₁-C₄)alkylamino radical; a di(C₁-C₄)alkylamino radicalwherein optionally the two alkyl groups, in conjunction with thenitrogen atom to which they are bonded, form a ring optionallyinterrupted by at least one heteroatom chosen from nitrogen, oxygen andsulfur; a heterocycle; a nitro radical; a phenyl radical; a carbonylradical; a ((C₁-C₄)alkoxy)carbonyl radical; a carboxamido radical; acyano radical; an amino radical; a sulfonyl radical; a —CO₂H radical, an—SO₃H radical; a —PO₃H₂ radical; a —PO₄H₂ radical; and a group offormula (II):

in which: R is chosen from oxygen and nitrogen; X is chosen from oxygen,an NH radical, and an NH(C₁-C₄)alkyl radical; and Y is chosen from ahydroxyl radical, an amino radical, a C₁-C₄ alkyl radical, a(C₁-C₄)alkoxy radical, a (C₁-C₄)alkylamino radical, and adi(C₁-C₄)alkylamino radical.
 2. The composition according to claim 1,wherein the at least one oxidation base is chosen from3-aminopyrazolo[1,5-a]pyridines of formula (Ia), acid addition saltsthereof, and base addition salts thereof:

in which: R₁, R₂ and R₃ are each independently chosen from: hydrogen; ahalogen; a hydroxyl radical; a (C₁-C₄)alkyl radical; a (C₁-C₄)alkylthioradical; a (C₁-C₄)alkoxy radical; an —NHSO₃H radical; an amino radical;a (C₁-C₄)alkylamino radical; a di(C₁-C₄)alkylamino radical whereinoptionally the two alkyl groups, in conjunction with the nitrogen atomto which they are bonded, form a ring optionally interrupted by at leastone heteroatom chosen from nitrogen, oxygen and sulfur; a heterocycle; asulfonamide radical; a carbonyl radical; a ((C₁-C₄)alkoxy)carbonylradical; a carboxamido radical; and a group of formula (II):

in which R is chosen from oxygen and nitrogen; X is chosen from oxygen,an NH radical, and an NH(C₁-C₄)alkyl radical; and Y is chosen from ahydroxyl radical, an amino radical, a C₁-C₄ alkyl radical, a(C₁-C₄)alkoxy radical, a (C₁-C₄)alkylamino radical, and adi(C₁-C₄)alkylamino radical.
 3. The composition according to claim 1,wherein the at least one oxidation base is chosen from:pyrazolo[1,5-a]pyridin-3-ylamine;2-acetylaminopyrazolo[1,5-a]pyridin-3-ylamine;2-morpholin-4-ylpyrazolo[1,5-a]pyridin-3-ylamine;3-aminopyrazolo[1,5-a]pyridine-2arboxylic acid;2-methoxypyrazolo[1,5-a]pyridin-3-ylamino;(3-aminopyrazolo[1,5-a]pyridin-7-yl)methanol;2-(3-aminopyrazolo[1,5-a]pyridin-5-yl)ethanol;2-(3-aminopyrazolo[1,5-a]pyridin-7-yl)ethanol;(3-aminopyrazolo[1,5-a]pyridin-2-yl)methanol;3,6-diaminopyrazolo[1,5-a]pyridine; 3,4-diaminopyrazolo[1,5-a]pyridine;pyrazolo[1,5-a]pyridine-3,7-diamine;7-morpholin-4-ylpyrazolo[1,5-a]pyridin-3-ylamine;pyrazolo[1,5-a]pyridine-3,5-diamine;5-morpholin-4-ylpyrazolo[1,5-a]pyridin-3-ylamine;2-[(3-aminopyrazolo[1,5-a]pyridin-5-yl(2-hydroxyethyl)amino]ethanol;2-[(3-aminopyrazolo[1,5-a]pyridin-7-yl)-(2-hydroxyethyl)amino]ethanol;3-aminopyrazolo[1,5-a]pyridin-5-ol; 3-aminopyrazolo[1,5-a]pyridin-4-ol;3-aminopyrazolo[1,5-a]pyridin-6-ol; 3-aminopyrazolo[1,5-a]pyridin-7-ol;their acid addition salts; and their base addition salts.
 4. Thecomposition according to claim 1, wherein the at least one oxidationbase is present in an amount ranging from 0.0005 to 12% by weight of thetotal weight of the dyeing composition.
 5. The composition according toclaim 4, wherein the at least one oxidation base is present in an amountranging from 0.005 to 6% by weight of the total weight of the dyeingcomposition.
 6. The composition according to claim 1, further comprisingat least one coupler chosen from meta-phenylenediamines,meta-aminophenols, meta-diphenols, and heterocyclic couplers.
 7. Thecomposition according to claim 6, wherein the at least one coupler ischosen from 2-methyl-5aminophenol,5-N-(β-hydroxyethyl)amino-2-methylphenol, 3-aminophenol,1,3-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene,4-chloro-1,3-dihydroxybenzene, 2,4-diamino-1-(β-hydroxyethyloxy)benzene,2-amino-4-(β-hydroxyethylamino)-1-methoxybenzene, 1,3-diaminobenzene,1,3-bis(2,4-diaminophenoxy)propane, sesamol, α-naphthol,2-methyl-1-naphthol, 6-hydroxyindole, 4-hydroxyindole,4-hydroxy-N-methylindole, 6-hydroxyindoline,2,6-dihydroxy-4-methylpyridine, 1H-3-methylpyrazol-5-one,1-phenyl-3-methylpyrazol-5-one, and their addition salts.
 8. Thecomposition according to claim 6, wherein the at least one coupler ispresent in an amount ranging from 0.0001 to 10% by weight of the totalweight of the dyeing composition.
 9. The composition according to claim8, wherein the at least one coupler is present in an amount ranging from0.005 to 5% by weight of the total weight of the dyeing composition. 10.The composition according to claim 1, further comprising at least oneadditional oxidation base chosen from para-phenylenediamines,bisphenylalkylenediamines, para-aminophenols, oitho-aminophenols, andheterocyclic bases other than the at least one oxidation base.
 11. Thecomposition according to claim 10, wherein the at least one additionaloxidation base is present in an amount ranging from 0.0005 to 12% byweight of the total weight of the dyeing composition.
 12. Thecomposition according to claim 11, wherein the at least one additionaloxidation base is present in an amount ranging from 0.005 to 6% byweight of the total weight of the dyeing composition.
 13. Thecomposition according to claim 1, wherein the acid addition salts arechosen from hydrochlorides, hydrobromides, sulfates, citrates,succinates, tartrates, lactates, phosphates, and acetates.
 14. Thecomposition according to claim 1, wherein the base addition salts arechosen from sodium hydroxide, potassium hydroxide, aqueous ammonia, andamines.
 15. A method of oxidation dyeing keratinous fibers, comprising:applying to the keratinous fibers, in an amount effective to dye thefibers, a dyeing composition comprising, in a medium appropriate fordyeing, at least one oxidation base chosen from3-aminopyrazolo[1,5a]pyridines of formula (I), acid addition saltsthereof, and base addition salts thereof:

in which: R₁, R₂, R₃, R₄ and R₅ are each independently chosen from:hydrogen; a halogen; an —NHSO₃H radical; a hydroxyl radical; a(C₁-C₄)alkyl radical; a (C₁-C₄)alkoxy radical; a (C₁-C₄)alkylthioradical; a (C₁-C₄)alkylamino radical; a di(C₁-C₄)alkylamino radicalwherein optionally the two alkyl groups, in conjunction with thenitrogen atom to which they are bonded, form a ring optionallyinterrupted by at least one heteroatom chosen from nitrogen, oxygen andsulfur; a heterocycle; a nitro radical; a phenyl radical; a carbonylradical; a ((C₁-C₄)alkoxy)carbonyl radical; a carboxamido radical; acyano radical; an amino radical; a sulfonyl radical; a —CO₂H radical, an—SO₃H radical; a —PO₃H₂ radical; a —PO₄H₂ radical; and a group offormula (II):

in which: R is chosen from oxygen and nitrogen; X is chosen from oxygen,an NH radical, and an NH(C₁-C₄)alkyl radical; and Y is chosen from ahydroxyl radical, an amino radical, a C₁-C₄ alkyl radical, a(C₁-C₄)alkoxy radical, a (C₁-C₄)alkylamino radical, and adi(C₁-C₄)alkylamino radical; and adding an oxidizing agent to the dyeingcomposition to develop a resulting color at acid, neutral or alkalinepH.
 16. The method according to claim 15, wherein the oxidizing agent isadded at the time of use.
 17. The method according to claim 15, whereinthe oxidizing agent is present in an oxidizing composition appliedsimultaneously or sequentially.
 18. The method according to claim 15,wherein the oxidizing agent is chosen from hydrogen peroxide, ureaperoxide, alkali metal bromates, persalts, peracids, and enzymes.
 19. Akit comprising: a first compartment containing a dyeing compositioncomprising, in a medium appropriate for dyeing, at least one oxidationbase chosen from 3-aminopyrazolo[1,5a]pyridines of formula (I), acidaddition salts thereof, and base addition salts thereof:

in which: R₁, R₂, R₃, R₄ and R₅ are each independently chosen from:hydrogen; a halogen; an —NHSO₃H radical; a hydroxyl radical; a(C₁-C₄)alkyl radical; a (C₁-C₄)alkoxy radical; a (C₁-C₄)alkylthioradical; a (C₁-C₄)alkylamino radical; a di(C₁-C₄)alkylamino radicalwherein optionally the two alkyl groups, in conjunction with thenitrogen atom to which they are bonded, form a ring optionallyinterrupted by at least one heteroatom chosen from nitrogen, oxygen andsulfur; a heterocycle; a nitro radical; a phenyl radical; a carbonylradical; a ((C₁-C₄)alkoxy)carbonyl radical; a carboxamido radical; acyano radical; an amino radical; a sulfonyl radical; a —CO₂H radical, an—SO₃H radical; a —PO₃H₂ radical; a —PO₄H₂ radical; and a group offormula (II):

in which: R is chosen from oxygen and nitrogen; X is chosen from oxygen,an NH radical, and an NH(C₁-C₄)alkyl radical; and Y is chosen from ahydroxyl radical, an amino radical, a C₁-C₄ alkyl radical, a(C₁-C₄)alkoxy radical, a (C₁-C₄)alkylamino radical, and adi(C₁-C₄)alkylamino radical; and a second compartment containing anoxidizing composition.
 20. 3-Aminopyrazolo[1,5-a]pyridines of formula(I′); acid addition salts thereof, and base addition salts thereof:

in which: R′₁ is chosen from: hydrogen; a halogen; a hydroxyl radical; a(C₁-C₄)alkyl radical; a (C₁-C₄)alkylthio radical; a (C₁-C₄)alkoxyradical; an amino radical; a (C₁-C₄)alkylamino radical; adi(C₁-C₄)alkylamino radical wherein optionally the two alkyl radicals,in conjunction with the nitrogen atom to which they are bonded, form aring optionally interrupted by at least one heteroatom chosen fromnitrogen, oxygen, and sulfur; a heterocycle; and a group of formula(II′) below:

in which: R′ is chosen from oxygen and nitrogen; X′ is chosen fromoxygen, an NH radical, and an NH(C₁-C₄)alkyl radical; and Y′ is chosenfrom a hydroxyl radical, an amino radical, a C₁-C₄ alkyl radical, a(C₁-C₄)alkoxy radical, a (C₁-C₄)alkylamino radical, and adi(C₁-C₄)alkylamino radical; R′₂ and R′₃ are each independently chosenfrom hydrogen; a halogen; a nitro radical; a heterocycle; an NHSO₃Hradical; a sulfonamide radical; a (C₁-C₄)alkyl radical substituted by atleast one radical chosen from heterocycles, —CO₂H, —SO₃H, —PO₃H₂,—PO₄H₂, hydroxyl, tri(C₁-C₄)alkylammonium, —NHSO₃H, sulfonamide, amino,(C₁-C₄)alkylamino, a di(C₁-C₄)alkylamino wherein optionally the twoalkyl radicals, in conjunction with the nitrogen atom to which they arebonded, form a ring optionally interrupted by at least one heteroatomchosen from nitrogen, sulfur, and oxygen; a (C₁-C₄)alkylthio radicalsubstituted by at least one radical chosen from hydroxyl, substitutedand unsubstituted amino radicals, —CO₂H, —SO₃H, —PO₃H₂, and —PO₄H₂, anda heterocycle; a (C₁-C₄)alkoxy radical substituted by at least oneradical chosen from hydroxyl, substituted and unsubstituted aminoradicals, —CO₂H, —SO₃H, —PO₃H₂, and —PO₄H₂, and a heterocycle; an aminoradical substituted by at least one (C₁-C₄)alkyl radical, said at leastone alkyl radical optionally substituted by at least one radical chosenfrom substituted and unsubstituted amino groups,tri(C₁-C₄)alkylammonium, —CO₂H, —SO₃H, —PO₃H₂, —PO₄H₂, —NHSO₃H, and aheterocycle; with the proviso that: at least one of the radicals R′₁ toR′₃ is a group other than hydrogen; the radicals R′₂ and R′₃ cannotsimultaneously be hydrogen; when R′₁ is a heterocycle, R′₂ and R′₃ aregroups other than a halogen and hydrogen; when R′₁ is hydrogen and whenone of the radicals R′₂ or R′₃ are hydrogen, the other radical R′₂ orR′₃ is a group other than a hydroxymethyl radical in position 7 or otherthan a β-hydroxyethyl radical in position 7 or 5; when R′₁ is a methoxyradical and when one of the radicals R′₂ or R′₃ is hydrogen, the otherradical R′₂ or R′₃ is a group other than chlorine. 21.3-Aminopyrazolo[1,5-a]pyridines of formula (I′) according to claim 20,chosen from: 5-pyridin-4-ylpyrazolo[1,5-a]pyridin-3-ylamine;4-(3-aminopyrazolo[1,5-a]pyridin-5-yl)-1-methylpyridinium;4-(3-aminopyrazolo[1,5-a]pyridin-5-yl)-1-(2-hydroxyethyl)pyridinium;(3-aminopyrazolo[1,5-a]pyridin-2-yl)pyridin-2-ylmethanol;2-[(3-aminopyrazolo[1,5-a]pyridin-2-yl)hydroxymethyl]-1-methylpyridinium;2-[(3-aminopyrazolo[1,5-a]pyridin-2-yl)hydroxymethyl]-1-(2-hydroxyethyl)pyridinium;N-7-(2-imidazo-1-ylpropyl)pyrazolo[1,5-a]pyridine-3,7-diamine;3-[2-(3-aminopyrazolo[1,5-a]pyridin-7-ylamino)propyl]-1-methyl-3H-imidazol-1-ium;3-[2-(3-aminopyrazolo[1,5-a]pyridin-7-ylamino)propyl]-1-(2-hydroxyethyl)-3H-imidazol-1-ium;N-5-(3-imidazo-1-ylpropyl)pyrazolo[1,5-a]pyridine-3,5-diamine;3-[3-(3-aminopyrazolo[1,5-a]pyridin-5-ylamino)propyl]-1-methyl-3H-imidazol-1-ium;3-[3-(3-aminopyrazolo[1,5-a]pyridin-5-ylamino)propyl]-1-(2-hydroxyethyl)-3H-imidazol-1-ium;their acid addition salts; and their base addition salts. 22.3-Aminopyrazolo[1,5-a]pyridines according to claim 20, wherein the acidaddition salts are chosen from hydrochlorides, hydrobromides, sulfates,citrates, succinates, tartrates, lactates, phosphates, and acetates. 23.3-Aminopyrazolo[1,5-a]pyridines according to claim 20, wherein the baseaddition salts are chosen from sodium hydroxide, potassium hydroxide,aqueous ammonia, and amines.
 24. A method of dyeing keratinous fibers,comprising: applying to the keratinous fibers, in an amount effective todye the fibers, a dyeing composition comprising, in a medium appropriatefor dyeing, at least one oxidation base chosen from: (a)3-aminopyrazolo[1,5a]pyridines of formula (I), acid addition saltsthereof, and base addition salts thereof:

in which: R₁, R₂, R₃, R₄ and R₅ are each independently chosen from:hydrogen; a halogen; an —NHSO₃H radical; a hydroxyl radical; a(C₁-C₄)alkyl radical; a (C₁-C₄)alkoxy radical; a (C₁-C₄)alkylthioradical; a (C₁-C₄)alkylamino radical; a di(C₁-C₄)alkylamino radicalwherein optionally the two alkyl groups, in conjunction with thenitrogen atom to which they are bonded, form a ring optionallyinterrupted by at least one heteroatom chosen from nitrogen, oxygen andsulfur; a heterocycle; a nitro radical; a phenyl radical; a carbonylradical; a ((C₁-C₄)alkoxy)carbonyl radical; a carboxamido radical; acyano radical; an amino radical; a sulfonyl radical; a —CO₂H radical, an—SO₃H radical; a —PO₃H₂ radical; a —PO₄H₂ radical; and a group offormula (II):

in which: R is chosen from oxygen and nitrogen; X is chosen from oxygen,an NH radical, and an NH(C₁-C₄)alkyl radical; and Y is chosen from ahydroxyl radical, an amino radical, a C₁-C₄ alkyl radical, a(C₁-C₄)alkoxy radical, a (C₁-C₄)alkylamino radical, and adi(C₁-C₄)alkylamino radical; (b) 3-aminopyrazolo[1,5-a]pyridines offormula (Ia), acid addition salts thereof, and base addition saltsthereof:

in which: R₁, R₂ and R₃ are each independently chosen from hydrogen; ahalogen; a hydroxyl radical; a (C₁-C₄)alkyl radical; a (C₁-C₄)alkylthioradical; a (C₁-C₄)alkoxy radical; an —NHSO₃H radical; an amino radical;a (C₁-C₄)alkylamino radical; a di(C₁-C₄)alkylamino radical whereinoptionally the two alkyl groups, in conjunction with the nitrogen atomto which they are bonded, form a ring optionally interrupted by at leastone heteroatom chosen from nitrogen, oxygen and sulfur; a heterocycle; asulfonamide radical; a carbonyl radical; a ((C₁-C₄)alkoxy)carbonylradical; a carboxamido radical; and a group of formula (II):

in which R is chosen from oxygen and nitrogen; X is chosen from oxygen,an NH radical, and an NH(C₁-C₄)alkyl radical; and Y is chosen from ahydroxyl radical, an amino radical, a C₁-C₄ alkyl radical, a(C₁-C₄)alkoxy radical, a (C₁-C₄)alkylamino radical, and adi(C₁-C₄)alkylamino radical; and (c) 3-Aminopyrazolo[1,5-a]pyridines offormula (I′); acid addition salts thereof, and base addition saltsthereof:

in which: R′₁ is chosen from: hydrogen; a halogen; a hydroxyl radical; a(C₁-C₄)alkyl radical; a (C₁-C₄)alkylthio radical; a (C₁-C₄)alkoxyradical; an amino radial; a (C₁-C₄)alkylamino radical; adi(C₁-C₄)alkylamino radical wherein optionally the two alkyl radicals,in conjunction with the nitrogen atom to which they are bonded, form aring optionally interrupted by at least one heteroatom chosen fromnitrogen, oxygen, and sulfur; a heterocycle; and a group of formula(II′) below:

in which: R′ is chosen from oxygen and nitrogen; X′ is chosen fromoxygen, an NH radical, and an NH(C₁-C₄)alkyl radical; and Y′ is chosenfrom a hydroxyl radical, an amino radical, a C₁-C₄ alkyl radical, a(C₁-C₄)alkoxy radical, a (C₁-C₄)alkylamino radical, and adi(C₁-C₄)alkylamino radical; R′₂ and R′₃ are each independently chosenfrom hydrogen; a halogen; a nitro radical; a heterocycle; an NHSO₃Hradical; a sulfonamide radical; a (C₁-C₄)alkyl radical substituted by atleast one radical chosen from heterocycles, —CO₂H, —SO₃H, —PO₃H₂,—PO₄H₂, hydroxyl, tri(C₁-C₄)alkylammonium, —NHSO₃H, sulfonamide, amino,(C₁-C₄)alkylamino, a di(C₁-C₄)alkylamino wherein optionally the twoalkyl radicals, in conjunction with the nitrogen atom to which they arebonded, form a ring optionally interrupted by at least one heteroatomchosen from nitrogen, sulfur, and oxygen; a (C₁-C₄)alkylthio radicalsubstituted by at least one radical chosen from hydroxyl, substitutedand unsubstituted amino radicals, —CO₂H, —SO₃H, —PO₃H₂, and —PO₄H₂, anda heterocycle; a (C₁-C₄)alkoxy radical substituted by at least oneradical chosen from hydroxyl, substituted and unsubstituted aminoradicals, —CO₂H, —SO₃H, —PO₃H₂, and —PO₄H₂, and a heterocycle; an aminoradical substituted by at least one (C₁-C₄)alkyl radical, said at leastone alkyl radical optionally substituted by at least one radical chosenfrom substituted and unsubstituted amino groups,tri(C₁-C₄)alkylammonium, —CO₂H, —SO₃H, —PO₃H₂, —PO₄H₂, —NHSO₃H, and aheterocycle; with the proviso that: at least one of the radicals R′₁ toR′₃ is a group other than hydrogen; the radicals R′₂ and R′₃ cannotsimultaneously be hydrogen; hen R′₁ is a heterocycle, R′₂ and R′₃ aregroups other than a halogen and hydrogen; when R′₁ is hydrogen and whenone of the radicals R′₂ or R′₃ are hydrogen, the other radical R′₂ orR′₃ is a group other than a hydroxymethyl radical in position 7 or otherthan a β-hydroxyethyl radical in position 7 or 5; when R′₁ is a methoxyradical and when one of the radicals R′₂ or R′₃ is hydrogen, the otherradical R′₂ or R′₃ is a group other than chlorine.